Gakuen Shimai

Sousuke is an average student, except for his hobby of taking candid pictures. His favourite model is Nanase Arisa, one of the school's idols. This is set to change when his father and Arisa's mother marry. All of a sudden he finds himself living with Arisa, and her equally hot sister Mika. It doesn't take long for Mika to catch Sousuke masturbating to one of his snapshots - and with that his dull and sad life changes to one of debauchery and lust with his two new sisters...